Membrane separation devices can be used in a variety of fields. In some cases, membrane separation devices can be used to purify water. For example, sea water can be purified in a membrane separation device using reverse osmosis to provide drinking water. In wastewater treatment, membrane separation devices can be used to remove particles, colloids, and macromolecules to disinfect the wastewater.
Membrane separation devices can include one or more spiral membrane units. A spiral membrane configuration is often used so that a flat sheet membrane can be efficiently packaged within a small space. A spiral membrane configuration can be packaged within a cartridge to form a spiral membrane unit. The spiral membrane units are typically loaded into a cylindrical device housing. The cylindrical device housing can contain the pressure applied to the fluid passing through the spiral membrane unit, as high pressures can be important for an efficient separation process.
As the pressurized feed flow is introduced into the end of a device housing, a seal along the outside surface of the spiral membrane unit is used to ensure that feed fluid is directed into the spiral membrane unit's flow channels and not into an annular space between the device housing walls and the spiral membrane unit. The seal can be located about the periphery of a seal plate. Prior art devices typically used seals with a chevron cross section, as shown in FIGS. 2A and 2B. A chevron cross-section seal 18 can require that each spiral membrane unit E be inserted into a housing 9 in the direction of feed flow 7. Each spiral membrane unit E is thus removed by pushing each spiral membrane unit E all the way through the device housing 9 in the feed flow direction. As a consequence, facilities that include the use of spiral membrane units E include building layouts that provide access at both sides of the cylindrical housing for inserting and removing the spiral membrane units during maintenance.